the solenoid force size and what factors

 the solenoid force size and what factors
Electromagnet magnetic size and what factors related
1 Current Size
The use of batteries, nails, Drawer magnets small nails, by changing the number of batteries, pick up nails quantity drawn: current, magnetic big.
2 winding turns
As described above, in the case of the same current, changing the number of turns, the number of pick up nails drawn: number of turns, a large magnetic force.
3. Whether the core
As above, current is constant, the number of turns unchanged compared insert core and coreless pick up nails when the number of results: There are core, magnetic large